To identify the source of the latch contention and format the contention
activity output, take the following steps:
- If your suspected contention situation involves a system
hang, take an SVC dump on all systems in the sysplex before you do
anything else. If you have to contact the IBM® Support Center, you might be asked to provide
this information. See the SVC dump topic in z/OS MVS Diagnosis: Tools and Service Aids.
- To verify that your problem is really latch contention, issue DISPLAY
GRS,LATCH,CONTENTION on each system to see if message ISG343I
displays any latches in contention.
- If ISG343I does display latches in contention, issue command DISPLAY
OMVS,WAITERS. Read the DISPLAY OMVS,WAITERS output
displayed in message BPXO063I for latch contention activity information.
The message BPXO063 can provide the following output tables: MOUNT
LATCH ACTTIVIY, OUTSTANDING CROSS SYSTEM MESSAGES, RECEIVED
SYSTEM MESSAGES, FILE SYSTEM LATCH ACTIVITY,
and OTHER WAITING THREADS.
- If you see MOUNT LATCH ACTIVITY displayed in
the message BPXO063I, you have mount latch contention. See Analyze the mount latch contention for more diagnosis information.
- If you see FILE SYSTEM LATCH ACTIVITY displayed
in the message, you have file system latch contention. See Analyze the file system latch contention for more diagnosis information.
- If you see FILE LATCH ACTIVITY displayed in the
message, you have file system latch contention. See Analyze the file latch contention for more diagnosis information.